Description

If you give yourself xp with the xp command to be level 2035 and stand on a drain, it works. If you get level 2036 after that, it extracts infinite xp and your level/experience never goes down.
The reverse is also true. Level 2036 won't make your xp bar drain. As soon as you set your xp to level 2035 it works properly again.
Relayed from FTBTeam/FTB-Modpack-Issues#531

Versions

Modpack FTB OceanBlock 1.11.0
Minecraft 1.16.5
Forge 36.2.20
Mob Grinding Utils mob_grinding_utils-1.16.5-0.4.30.jar

Thanks again :)